Avascular necrosis (AVN), which is also known as osteonecrosis (ON), ischemic bone necrosis, or aseptic necrosis, is a debilitating disease resulting from the temporary or permanent loss of circulation to the bones resulting in localized bone death. The loss of proper blood flow can result from trauma or compromising conditions such as, for example, prolonged steroid use, alcohol use, gout diabetes, pancreatitis, venous occlusion, decompression disease, radiation therapy, chemotherapy, and Gaucher's disease.
AVN of the femoral head is a debilitating condition with oftentimes fast progression. Severe pain and limitation of movement can ensue in as short as two years with a 70–80% chance of complete collapse of the bone and surrounding articulating surface after three years if left untreated. For most patients, treatment becomes an ongoing process which inevitably results in arthroplasty. Various treatments for AVN which focus on salvaging the head of the femur or other bone or joint include core decompression, osteomy, bone grafting, and vascularized fibular grafting.
The latter is a surgical procedure in which an autologous fibular graft implant is used to support the head of the femur. The necrotic tissue is first removed and packed with autologous cancellous bone leaving room for the insertion of an autologous fibular graft with its vascular pedicle, the peroneal vessels, attached. To provide abundant blood flow to the head of femur, an anastomosis is performed between the lateral circumflex vessels and the fibula vascular pedicle. Although the procedure is oftentimes successful in stabilizing the femoral head and providing blood flow to the head, it carries the risk for donor sight morbidity, including, but not limited to, temporary loss of sensory function with the potential for compromised motor function in the distal part of the leg where the fibular graft was taken.
U.S. Pat. No. 6,679,890 discusses another method and device for treating AVN of the femoral head. The device disclosed in U.S. Pat. No. 6,679,890 augments the femoral head with bone cement. An open ended and fenestrated tube is inserted through a hole into the femoral neck and uncured bone cement is injected and cured at high pressure.